The first inhabitants of what is now Xinjiang, the north-western region of China, were of strikingly European appearance. Their bodies have been preserved as mummies by the intensely dry, salty nature of the region, as have their clothes, which show great sophistication in weaving and in some cases have perfectly preserved rich colours, as vivid as if they'd been woven recently.

Between the Tian Shan Mountains to the north and the Kunlun Range to the south lies the Tarim Basin. The River Tarim and other such watercourses as there are drain into it, and form what is now a fairly small lake, Lop Nor, amid a vast salt plain. Almost all the Tarim Basin is now the Taklamakan Desert, one of the most arid regions of the earth. The relative locations and sizes of desert, lake, and rivers have varied over the centuries and millennia, and human habitations have clung onto the edges wherever an oasis could support a town.

The main discoveries of mummies have been near the little towns of Loulan, Cherchen, and Hami, on the eastern edge of the Taklamakan. Those found in earlier times were sketched, looted, or left to rot; the modern interest in them came with the availability of modern techniques of preservation, and they are now on display in the museum in the Xinjiang regional capital, Ürümchi (pinyin Ürümqi).

In 1999 Elizabeth Wayland Barber, an expert on ancient textiles, published a book The Mummies of Ürümchi, covering every aspect of these people, including enough of a beginner's guide to linguistics, plate tectonics, carbon dating, and so on to explain how she ties all these aspects together. Her main interest of course is in the cloth, and she explains not only how exactly twill, felt, tapestry, and other forms are made, but why they are appropriate, in terms of loom technology, and the availability of domesticated animals and plants.

Although mainly habitable only by nomadic herders, the Tarim Basin has always been of great importance as the link between China and the Silk Road leading to Samarkand, Bactria, and thence to the Middle East and the Roman Empire and its successors. To the south is the Indian subcontinent, accessible by the high Karakoram Pass, and to the north are the steppes of the horse-riding Turkic people. The Jade Gate, in the far western end of the Great Wall of China, was China's point of entry into the region: they made contact perhaps around 100 BCE, with the people they called the Yuezhi.

China has exerted some kind of control over Xinjiang ("new province") for a long time, but only since the Communist takeover in 1949 have ethnic Chinese moved in in large numbers; but outside Ürümchi the people are still mainly the Turkic-speaking Uyghur. These differ from the usual run of Asian-looking Turkic peoples by having a good smattering of genes that can make them look like Europeans. They are relics of two populations that lived there before the Turkic nomads moved in.

The oldest mummies date from around 2000 BCE, and this appears to have been the earliest settlement of the area. Geological reasons (the thawing of a little ice age) rule out anything much earlier. They continue to about 1000 BCE, and have burial grounds marked by distinctive circular and sun patterns of tree trunks. Dr Barber's examination of the weaving styles and techniques leads her to believe these people were Celts or closely related. The kind of looms implied by their weaving suggest that they originated in Russia north of the Caucasus, and were among the first Proto-Indo-European speakers to leave that ancestral homeland, some going west into Europe to become Celts, and others going east and eventually into the Tarim Basin. The most familiar Celtic tartan weave is early-modern Scottish design in kilts and plaids, but ancient examples have been preserved in the salt mines of the Celtic Hallstatt culture in Central Europe.

Much later, the Tocharians appeared in Xinjiang. These were identified in the nineteenth century by their Buddhist texts written in a known Indian script, but which turned out to be a hitherto unknown Indo-European language, or rather two closely related ones, Tocharian A and Tocharian B. Contemporary paintings of Tocharians, known in Chinese as Yuezhi, show them also to have distinctly European features. While this is also true of some other people in the mountainous regions to the south, who speak Indo-Iranian languages, and who would have been in the path to bring Buddhism from India to China, the surprising thing about Tocharian is that it is much closer to the Celtic branch of Indo-European than to the Indian branch.

However, it is likely that the Tocharians were not descendants of the original European (or rather 'Caucasian') inhabitants of the area, but a separate later migration. Tocharian is a cousin of Celtic, not a descendant.

It turns out that China borrowed quite a bit culturally from Indo-European peoples, including words for 'chariot' and 'magician' (the actual Persian word magus) and associated concepts. Weaving techniques were no exception, and it may have been the people behind the mummies of Ürümchi who transmitted this culture from west to east.